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Annotation of src/usr.bin/head/head.1, Revision 1.20

1.20    ! jmc         1: .\"    $OpenBSD: head.1,v 1.19 2011/12/28 01:52:33 schwarze Exp $
1.7       aaron       2: .\"
1.1       deraadt     3: .\" Copyright (c) 1980, 1990 The Regents of the University of California.
                      4: .\" All rights reserved.
                      5: .\"
                      6: .\" Redistribution and use in source and binary forms, with or without
                      7: .\" modification, are permitted provided that the following conditions
                      8: .\" are met:
                      9: .\" 1. Redistributions of source code must retain the above copyright
                     10: .\"    notice, this list of conditions and the following disclaimer.
                     11: .\" 2. Redistributions in binary form must reproduce the above copyright
                     12: .\"    notice, this list of conditions and the following disclaimer in the
                     13: .\"    documentation and/or other materials provided with the distribution.
1.11      millert    14: .\" 3. Neither the name of the University nor the names of its contributors
1.1       deraadt    15: .\"    may be used to endorse or promote products derived from this software
                     16: .\"    without specific prior written permission.
                     17: .\"
                     18: .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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                     30: .\"    from: @(#)head.1        6.6 (Berkeley) 7/24/91
                     31: .\"
1.20    ! jmc        32: .Dd $Mdocdate: December 28 2011 $
1.1       deraadt    33: .Dt HEAD 1
                     34: .Os
                     35: .Sh NAME
                     36: .Nm head
1.4       aaron      37: .Nd display first few lines of files
1.1       deraadt    38: .Sh SYNOPSIS
                     39: .Nm head
1.18      jmc        40: .Op Fl Ns Ar count | Fl n Ar count
1.1       deraadt    41: .Op Ar
                     42: .Sh DESCRIPTION
1.4       aaron      43: The
                     44: .Nm
                     45: utility copies the first
1.1       deraadt    46: .Ar count
1.4       aaron      47: lines of each specified
                     48: .Ar file
                     49: to the standard output.
1.5       aaron      50: If no files are named,
1.4       aaron      51: .Nm
                     52: copies lines from the standard input.
1.1       deraadt    53: If
                     54: .Ar count
1.4       aaron      55: is omitted, it defaults to 10.
                     56: .Pp
                     57: The options are as follows:
                     58: .Bl -tag -width Ds
1.18      jmc        59: .It Fl Ns Ar count | Fl n Ar count
1.4       aaron      60: Copy the first
                     61: .Ar count
                     62: lines of each input file to the standard output.
                     63: .Ar count
                     64: must be a positive decimal integer.
                     65: .El
                     66: .Pp
                     67: If more than one file is specified,
                     68: .Nm
                     69: precedes the output of each file with the following, in order to distinguish
                     70: the head of each file:
                     71: .Pp
                     72: .Dl ==> Ar file No <==
1.17      jmc        73: .Sh EXIT STATUS
1.16      jmc        74: .Ex -std head
1.4       aaron      75: .Sh EXAMPLES
                     76: To display the first 500 lines of the file
                     77: .Ar foo :
                     78: .Pp
1.20    ! jmc        79: .Dl $ head -n 500 foo
1.4       aaron      80: .Pp
                     81: .Nm
                     82: can be used in conjunction with
                     83: .Xr tail 1
                     84: in the following way to, for example, display only line 500 from the file
                     85: .Ar foo :
                     86: .Pp
1.20    ! jmc        87: .Dl $ head -n 500 foo | tail -1
1.1       deraadt    88: .Sh SEE ALSO
1.4       aaron      89: .Xr cat 1 ,
                     90: .Xr less 1 ,
                     91: .Xr more 1 ,
1.1       deraadt    92: .Xr tail 1
1.12      jmc        93: .Sh STANDARDS
1.3       aaron      94: The
                     95: .Nm
1.13      jmc        96: utility is compliant with the
1.15      jmc        97: .St -p1003.1-2008
1.13      jmc        98: specification.
                     99: .Pp
1.20    ! jmc       100: The historic syntax
        !           101: .Fl Ns Ar count
        !           102: is supported by this implementation.
1.1       deraadt   103: .Sh HISTORY
                    104: The
1.3       aaron     105: .Nm
1.19      schwarze  106: utility first appeared in
                    107: .Bx 1 .
                    108: .Sh AUTHORS
                    109: .An Bill Joy ,
                    110: August 24, 1977.